Increasing pressure support during vibrocompression is useful during respiratory therapy?

Introduction

ICU inpatients are susceptible to events of transient hypoxemia. The physical therapist makes use of bronchial hygiene techniques to solve or alleviate this problem. The goal of this paper was to compare two physiotherapy techniques: vibrocompression versus vibrocompression plus increase of 10 cmH₂O in inspiratory pressure (IP) during pressure support ventilation (PSV).

Methods

After being placed in the supine position in bed, with head angle elevation at 30°, patients were randomized to: group 1 (G1): vibrocompression for 10 minutes in the chest, or group 2 (G2): vibrocompression plus increase of 10 cmH₂O in IP in PSV for 10 minutes in the chest. Clinical variables and APACHE II score were registered. Parameters analyzed at the beginning (1) and at the end (2) of the protocol were: variation of peak pressure (ΔPP = Pp2 - Pp1), variation of tidal volume (ΔVT = VT2 - VT1), variation of dynamic compliance (ΔCdyn = Cdyn2 - Cdyn1). The amount of variation of mucus secretion aspirated (ΔSa = Sa2 - Sa1) at the end was also measured. The results are showed in mean ± SD.

Results

Both groups (G1: n = 30 and G2: n = 39) were similar in clinical characteristics and APACHE II score. The variation of variables in G1 and G2, were respectively: ΔPp (cmH₂O) = 0.58 ± 1.41 and -0.10 ± 0.98, P = 0.02; ΔVT (ml) = 28.90 ± 119.40 and 64.26 ± 93.82, P = 0.96; ΔCdyn (cmH₂O) = 3.03 ± 9.56 and 4.26 ± 8.24, P = 0.89; ΔSa (g) 0.29 ± 1.73 and 0.93 ± 2.28, P = 0.36.

Conclusions

We found no differences between groups, except in peak pressure (Pp2 >Pp1) that was greater in G1. This result could be probably due to decreased airway resistance.